Introduction

 In this article we will see how to use Network Emulator Toolkit to test an application in limitted network bandwidth.

Background 

 It is often a requirement that we need to test our application in limited bandwidth for performance test. We may want to put demand on a system or device and measure its response to determine a system’s behavior under both normal and anticipated peak load conditions. It helps to identify the maximum operating capacity of an application as well as any bottlenecks and determine which element is causing degradation. To help us in these testing we have a tool which is called Network Emulator for Windows Toolkit (NEWT). NEWT is a software-based solution that can emulate the behavior of both wired and wireless networks using a reliable physical link, such as an Ethernet. It is available in a 32 Bits version and a 64 Bits version.

Table of contents

1. configure Network Emulator Client for limited bandwidth

1. Network Emulator Toolkit

Download and install Network Emulator Toolkit. Network emulator toolkit is available as 32 and 64 bit versions. Find the one appropriate for your use. You can find network emulator toolkit from the below links.

Network Emulator Toolkit 32-Bits

Network Emulator Toolkit 64-Bits

How to test an application in limited bandwidth using Network Emulator Toolkit

Now open Network Emulator Client in administrator mode. This will open up Network Emulator Client as shown in the figure below.

Now we have to configure it according to our need. Here what i am going to show is How to configure Network Emulator Client to create an unstable network where the packets will be loosed in regular interval. 

How to configure Network Emulator Client for limited bandwidth

Now we are going to create a channel. Channel is your new configuration.

Goto Configuration->New Channel

Now select your desired connection from the drop down. Here i am going to select Dial-up 56k.

Now to the new channel we are going to add a link. For this Go to Configuration->New Link

After adding new link we need to set UpStream and DownStream limits.

For this right click on the link image and set Upstream and downstream configurations.

Once you click on UpStream, you will get a window to which you can add your configuration.

In this window, configure the packet loss. By default it will be no loss. Change it to periodic loss. Here we are setting it to 2 ie. when 2 packets are sent one packet will miss. Similarly set the downstream configuration by right clicking on the link and say set Downstream. Make the packet loss to 2.

After this we need to add a filter. For this go to Configuration->New Filter

It will open a configuration window. Click on the add button which will add one entry in the grid below with one check-box. select that check-box and close it. Now start the application by clicking start button.

That is it! now your network will behave as what you have configured and you can run your application against  it to test your application in limited bandwidth. Similarly you can change the configuration to meet your requirements of your testing. :)